Toxin

A toxin is a harmful substance produced within living cells or organisms;[1][2] synthetic toxicants created by artificial processes are thus excluded. The term was first used by organic chemist Ludwig Brieger (1849–1919),[3] derived from the word toxic.[4]

This article is about the class of poisonous substances. For other uses, see Toxin (disambiguation).

Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to almost immediately deadly (such as botulinum toxin). Toxins are largely secondary metabolites, which are organic compounds that are not directly involved in an organism's growth, development, or reproduction, instead often aiding it in matters of defense.

Terminology

Toxins are often distinguished from other chemical agents by their method of production—the word toxin does not specify method of delivery (compare with venom and the broader meaning of poison—all substances that can also cause disturbances to organisms). It simply means it is a biologically produced poison.

According to an International Committee of the Red Cross review of the Biological Weapons Convention, "Toxins are poisonous products of organisms; unlike biological agents, they are inanimate and not capable of reproducing themselves", and "Since the signing of the Constitution, there have been no disputes among the parties regarding the definition of biological agents or toxins".[5]

According to Title 18 of the United States Code, "... the term "toxin" means the toxic material or product of plants, animals, microorganisms (including, but not limited to, bacteria, viruses, fungi, rickettsiae or protozoa), or infectious substances, or a recombinant or synthesized molecule, whatever their origin and method of production..."[6]

A rather informal terminology of individual toxins relates them to the anatomical location where their effects are most notable:

On a broader scale, toxins may be classified as either exotoxins, being excreted by an organism, or endotoxins, that are released mainly when bacteria are lysed.

Biotoxins

The term "biotoxin" is sometimes used to explicitly confirm the biological origin.[7][8] Biotoxins can be further classified, for example, as fungal biotoxins, microbial toxins, plant biotoxins, or animal biotoxins.

Toxins produced by microorganisms are important virulence determinants responsible for microbial pathogenicity and/or evasion of the host immune response.[9]

Biotoxins vary greatly in purpose and mechanism, and can be highly complex (the venom of the cone snail contains dozens of small proteins, each targeting a specific nerve channel or receptor), or relatively small protein.

Biotoxins in nature have two primary functions:

Some of the more well known types of biotoxins include:

Environmental toxins
See also: Environmental toxicology

The term "environmental toxin" can sometimes explicitly include synthetic contaminants[11] such as industrial pollutants and other artificially made toxic substances. As this contradicts most formal definitions of the term "toxin", it is important to confirm what the researcher means when encountering the term outside of microbiological contexts.

Environmental toxins from food chains that may be dangerous to human health include:

Finding information about toxins

In general, when scientists determine the amount of a substance that may be hazardous for humans, animals and/or the environment they determine the amount of the substance likely to trigger effects and if possible establish a safe level. In Europe, the European Food Safety Authority produced risk assessments for more than 4,000 substances in over 1,600 scientific opinions and they provide open access summaries of human health, animal health and ecological hazard assessments in their: OpenFoodTox[22] database. [23][24] The OpenFoodTox database can be used to screen potential new foods for toxicity.[25]

The Toxicology and Environmental Health Information Program (TEHIP)[26] at the United States National Library of Medicine (NLM) maintains a comprehensive toxicology and environmental health web site that includes access to toxins-related resources produced by TEHIP and by other government agencies and organizations.[27] This web site includes links to databases, bibliographies, tutorials, and other scientific and consumer-oriented resources. TEHIP also is responsible for the Toxicology Data Network (TOXNET),[28] an integrated system of toxicology and environmental health databases that are available free of charge on the web.

TOXMAP is a Geographic Information System (GIS) that is part of TOXNET.[29] TOXMAP uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund Basic Research Programs.

Misuse of the term

When used non-technically, the term "toxin" is often applied to any toxic substance, even though the term toxicant would be more appropriate. Toxic substances not directly of biological origin are also termed poisons and many non-technical and lifestyle journalists follow this usage to refer to toxic substances in general.

In the context of quackery and alternative medicine, the term "toxin" is used to refer to any substance alleged to cause ill health. This could range from trace amounts of potentially dangerous pesticides, to supposedly harmful substances produced in the body by intestinal fermentation (auto-intoxication), to food ingredients such as table sugar, monosodium glutamate (MSG), and aspartame.[30]

See also

References
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  2. "toxin – Definition from the Merriam-Webster Online Dictionary". Retrieved 13 December 2008.
  3. Brade, Helmut (1999). Endotoxin in Health and Disease. CRC Press. ISBN 978-0824719449 – via Google Books.
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  5. "The Biological Weapons Convention – An overview". Retrieved 13 December 2008.
  6. "U.S. Code". Archived from the original on 21 July 2011. Retrieved 13 December 2008.
  7. "biotoxin – Definition from the Merriam-Webster Online Dictionary". Retrieved 13 December 2008.
  8. "biotoxin" at Dorland's Medical Dictionary
  9. Proft T, ed. (2009). Microbial Toxins: Current Research and Future Trends. Caister Academic Press. ISBN 978-1-904455-44-8.
  10. Dorland's Illustrated Medical Dictionary (32nd ed.). Philadelphia, PA: Saunders/Elsevier. 2012. p. 1236. ISBN 978-1-4160-6257-8.
  11. Grigg J (March 2004). "Environmental toxins; their impact on children's health". Archives of Disease in Childhood. 89 (3): 244–50. doi:10.1136/adc.2002.022202. PMC 1719840. PMID 14977703.
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  13. Oikawa H, Fujita T, Saito K, Satomi M, Yano Y (2008). "Difference in the level of paralytic shellfish poisoning toxin accumulation between the crabs Telmessus acutidens and Charybdis japonica collected in Onahama, Fukushima Prefecture". Fisheries Science. 73 (2): 395–403. doi:10.1111/j.1444-2906.2007.01347.x.
  14. Abouabdellah R, Taleb H, Bennouna A, Erler K, Chafik A, Moukrim A (April 2008). "Paralytic shellfish poisoning toxin profile of mussels Perna perna from southern Atlantic coasts of Morocco". Toxicon. 51 (5): 780–6. doi:10.1016/j.toxicon.2007.12.004. PMID 18237757.
  15. Wang L, Liang XF, Zhang WB, Mai KS, Huang Y, Shen D (November 2009). "Amnesic shellfish poisoning toxin stimulates the transcription of CYP1A possibly through AHR and ARNT in the liver of red sea bream Pagrus major". Marine Pollution Bulletin. 58 (11): 1643–8. doi:10.1016/j.marpolbul.2009.07.004. PMID 19665739.
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  18. Doucet E, Ross NN, Quilliam MA (September 2007). "Enzymatic hydrolysis of esterified diarrhetic shellfish poisoning toxins and pectenotoxins". Analytical and Bioanalytical Chemistry. 389 (1): 335–42. doi:10.1007/s00216-007-1489-3. PMID 17661021.
  19. Poli MA, Musser SM, Dickey RW, Eilers PP, Hall S (July 2000). "Neurotoxic shellfish poisoning and brevetoxin metabolites: a case study from Florida". Toxicon. 38 (7): 981–93. doi:10.1016/S0041-0101(99)00191-9. PMID 10728835.
  20. Morohashi A, Satake M, Murata K, Naoki H, Kaspar HF, Yasumoto T (1995). "Brevetoxin B3, a new brevetoxin nalog isolated from the greenshell mussel perna canaliculus involved in neurotoxic shellfish poisoning in new zealand". Tetrahedron Letters. 36 (49): 8995–98. doi:10.1016/0040-4039(95)01969-O.
  21. Morohashi A, Satake M, Naoki H, Kaspar HF, Oshima Y, Yasumoto T (1999). "Brevetoxin B4 isolated from greenshell mussels Perna canaliculus, the major toxin involved in neurotoxic shellfish poisoning in New Zealand". Natural Toxins. 7 (2): 45–8. doi:10.1002/(SICI)1522-7189(199903/04)7:2<45::AID-NT34>3.0.CO;2-H. PMID 10495465.
  22. "Chemical hazards data - OpenFoodTox". European Food Safety Authority. Retrieved 27 October 2019.
  23. Dorne JL, Richardson J, Kass G, Georgiadis N, Monguidi M, Pasinato L, Cappe S, Verhagen H, Robinson T (January 2017). "OpenFoodTox: EFSA's open source toxicological database on chemical hazards in food and feed". EFSA Journal. 15 (1): e15011. doi:10.2903/j.efsa.2017.e15011.
  24. Reilly L, Serafimova R, Partosch F, Gundert-Remy U, Cortiñas Abrahantes J, Dorne JM, Kass GE (October 2019). "Testing the thresholds of toxicological concern values using a new database for food-related substances". Toxicology Letters. 314: 117–123. doi:10.1016/j.toxlet.2019.07.019. PMID 31325634.
  25. Pearce JM, Khaksari M, Denkenberger D (April 2019). "Preliminary Automated Determination of Edibility of Alternative Foods: Non-Targeted Screening for Toxins in Red Maple Leaf Concentrate". Plants. 8 (5): 110. doi:10.3390/plants8050110. PMC 6571818. PMID 31027336.
  26. "Environmental Health and Toxicology Information". National Library of Medicine.
  27. Fonger GC, Stroup D, Thomas PL, Wexler P (January 2000). "TOXNET: A computerized collection of toxicological and environmental health information". Toxicology and Industrial Health. 16 (1): 4–6. doi:10.1177/074823370001600101. PMID 10798381.
  28. "TOXNET". toxnet.nlm.nih.gov. Archived from the original on 14 May 2019. Retrieved 29 September 2010.
  29. Hochstein C, Szczur M (24 July 2006). "TOXMAP: a GIS-based gateway to environmental health resources". Medical Reference Services Quarterly. 25 (3): 13–31. doi:10.1300/J115v25n03_02. PMC 2703818. PMID 16893844.
  30. ""Detoxification" Schemes and Scams". Quackwatch.
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